1994-1994 Error Codes
Thread Starter
Le Mans Master
Joined: Mar 2004
Posts: 5,107
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From: Dublin CA
1994-1995 Error Codes
Just a question that made me curious. What causes the error code recorded by the computer to change from a "C" Current to a "H" Historic code.
I am not getting any codes, just wondering since Kimmer had a Historic code H16 that he erased and it did not come back.
I am not getting any codes, just wondering since Kimmer had a Historic code H16 that he erased and it did not come back.
Last edited by John A. Marker; Aug 4, 2015 at 04:26 PM.
Team Owner
Joined: Sep 2003
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Some H codes require a specific number of key cycles to disappear. I've never seen anything that confirms how many except in the instance of some LTPWS, ABS etc. I believe there are actually H codes that maybe don't go away with devices most of us have to clear codes. Some diagnostics depends on the H codes I'm quite sure. A code by code read in the FSM might answer your question.
Race Director
Joined: Jan 2000
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From: Owings Mills, MD 21117
Some H codes require a specific number of key cycles to disappear. I've never seen anything that confirms how many except in the instance of some LTPWS, ABS etc. I believe there are actually H codes that maybe don't go away with devices most of us have to clear codes. Some diagnostics depends on the H codes I'm quite sure. A code by code read in the FSM might answer your question.
Thread Starter
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
The few codes that have shown up on my 95 I didn't not have a problem clearing. I was just wondering at what point it changed from current to history. In other words...I throw a code C16 today at 4:00 PM. My check engine light comes on (or not). I drive home, park the car. Start it up in the morning and the check engine light is not on. The following day for what ever reason I check for codes. Will I find the C16 or because I have turned the car off and on a couple of times? Or will the code will change from a C16 to a H16?
Team Owner
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I believe that it changes with every generation of ECM/BCM/CCM or combination of them. Each code could easily be different depending on the component it was reporting on. An emissions component would act differently than say an optional piece of equipment component.
I believe that generally speaking a current code is changed to a history code after specific key cycles with no repetition of the fault and likely remains until cleared or another specific number of key cycles when it goes away. Not all codes set the MIL on a first occurrence or sometimes never and is only seen when scanned.
Unless you have a specific occurrence it's actual foolish to even be concerned.
The ECM/BCM/PCM/CCM understands that shi! happens and just acknowledges the 'glitch' for a while.
I believe that generally speaking a current code is changed to a history code after specific key cycles with no repetition of the fault and likely remains until cleared or another specific number of key cycles when it goes away. Not all codes set the MIL on a first occurrence or sometimes never and is only seen when scanned.
Unless you have a specific occurrence it's actual foolish to even be concerned.
The ECM/BCM/PCM/CCM understands that shi! happens and just acknowledges the 'glitch' for a while.
